Members of Congress are uniting behind an effort to help free a former Marine who has been imprisoned in Iran for nearly two years.

More than 100 members of Congress signed a letter to Secretary of State John Kerry on July 17 requesting that he explore all opportunities to reunite Amir Hekmati with his family. The letter included 112 signatures from Democrats and Republicans, showing bipartisan support for freeing the former sergeant.

The effort was led by Rep. Dan Kildee, a Democrat from Hekmati’s home district in Flint, Mich. Kildee said what started as an important piece of advocacy for constituents in his district has turned into a deeply personal cause for him and his staff.

“Amir is a young man from my district who served his country with great distinction and honor,” Kildee told Marine Corps Times. “I’m their congressman, so I felt like I not only had an interest, but an obligation to help. ... My staff has really been working overtime on this.”

Hekmati served as an infantry rifleman from 2001 to 2005. He deployed to Iraq in 2003, making use of his knowledge of Arabic and Farsi there. When he got out of the Corps, he continued using his language skills and launched his own linguistics consulting service.

In 2011, before starting economics classes at the University of Michigan, Hekmati flew to Iran to visit his grandmother. But within weeks, he was arrested, interrogated and imprisoned. Hekmati has been held ever since on the allegation that he was there to spy for the CIA. At one point, Hekmati had been sentenced to death, but the decision was overturned on appeal.

Kildee said it’s possible that Hekmati’s time in the Marine Corps could have contributed to allegations by Iranian officials that he was there to spy. Since the Iranians are suspicious of the U.S. government and certainly the military, Kildee said, it’s likely his service has been a source of suspicion.

“But the fact that he served in the Marine Corps — and served well — by itself shouldn’t cause anyone to jump to conclusions,” he said.

Hekmati’s family has had little to no contact with the former Marine since he was arrested nearly two years ago. Kildee said the fact that the U.S. has no diplomatic relations with Iran makes it difficult to receive updates on his well-being, which has members of Congress concerned.

“Unfortunately information doesn’t flow much from Iran, so we’re hoping for the best,” he said. “[Members of Congress] are anxious to hear any updates.”

Laura Seal, a State Department spokeswoman, said the agency remains “very concerned” about Hekmati’s status. Although the Iranian courts lifted the death sentence and ordered a retrial over a year ago, Hekmati’s case remains in limbo and his status is uncertain, she said.

“Mr. Hekmati now has spent almost two years in prison on charges that are categorically false, and he endured a closed-door trial with little regard for fairness and transparency,” Seal told Marine Corps Times. “We remain concerned over reports of Mr. Hekmati’s health condition in prison and urge the Iranian government to release him so that he may be reunited with his family.”

Kildee said what ultimately grabbed his attention in the case is that Hekmati’s situation is the story of a family in distress. Hekmati’s dad was diagnosed with brain cancer in September. In Persian culture, it’s customary that the eldest son be responsible for family members in that situation. Kildee said hopes Iranian officials will recognize that Hekmati’s imprisonment is causing additional stress to a family already suffering.

“There are cultural and humanitarian reasons as well as legal arguments as to why he should be released,” Kildee said.

A spokesman for the Hekmati family said they are grateful for Kildee’s efforts as well as those by other members of Congress and everyone who has offered time, thoughts and prayers on behalf of the family.